Content described in this part merely provide background information related to embodiments of the present invention and do not configure a conventional art.
A mobile communication terminal has departed from the scope of a conventional simple communication device or an information provision device and has become an essential good of a modern person according to developments of a mobile communication network and a terminal specification, and is evolving as a total entertainment device.
Along with this, recently, a use of a smart phone in which a function of a communication terminal and a function of a personal digital assistant (PDA) are combined has become popularized. A smart phone is an intelligent terminal in which a computer support function such as Internet communication, information search, etc. is added to a mobile phone, a high capacity memory and a high performance central processing unit (CPU) are installed as compared with a conventional communication terminal, and an operating system (OS) for supporting various application executions, voice/data communication, PC connection, etc. is installed.
As one application technique using a smart phone, various location-based services providing convenience to a user (for example, vehicle navigation, a map, path finding, an indoor store guide, etc.) are being proposed and receiving much attention.
An important point in the location-based service is related to whether a position of a user can be precisely measured in some method.
Generally, a location tracking method using a global positioning system (GPS) is used for the location-based service used outdoors, but the GPS is not used indoors since it is difficult to communicate with a satellite indoors. Accordingly, positioning technology based on short range wireless communication technologies such as radio frequency identification (RFID), Bluetooth, and wireless-fidelity (Wi-Fi) are being mainly used indoors.
Cell-ID, triangular survey, fingerprint methods, etc. are examples of the positioning technology.
The Cell-ID method estimates a current position based on a nearest access point (AP) around a positioning target. This method can be simply implemented, but a positioning accuracy is poor. The triangular survey method basically provides a great position resolution, but generates a great position error due to a phenomenon such as multipath fading. Further, an implementation cost is increased in the method since a special device which can accurately measure information is required. Accordingly, the fingerprint method is preferred when compared with the two methods described above. The fingerprint method estimates a position by preselecting various arbitrary positions in a service region and using a received signal strength (RSS) collected from the selected positions.
The method has an advantage in that it alleviates an environmental factor through preliminarily information collection, but has disadvantages in that a time and a cost are required since a plurality of reference positions which are used for the positioning are required and the collection process is manually performed by a service manager.
Further, since the RSS is greatly changed according to an arrangement of an inside space, when a spatial arrangement is changed, the fingerprint has to be remeasured, and it is difficult to measure a precise position since there are various error factors.
In order to overcome the problems, various fingerprint map construction methods have been proposed, but a detailed method applying a constructed fingerprint map to marketing has not been proposed.